Malicious Office (OOXML) / .DOC — malware analysis report

Static analysis result for SHA-256 7d58275a08f80b68…

MALICIOUS

Office (OOXML) / .DOC

866.2 KB Created: 2022-09-26 12:15:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-09-26
MD5: 39e9bea9c5ab21d972bb27115b4d4320 SHA-1: 3cbf53e5a1247a9db30c8f64bcfbc59c1d0b88fe SHA-256: 7d58275a08f80b689b595cabd092d8466ab645db8de60b9cfde04b89738ff778
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1071.001 Web Protocols

The sample contains a critical heuristic for an obfuscated auto-exec VBA loader that uses Shell() and CreateObject() calls. ClamAV also detected the file as 'Xls.Dropper.Valyria-10012499-0', indicating it's a known dropper. The VBA macro likely downloads and executes a second-stage payload.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Dropper.Valyria-10012499-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Valyria-10012499-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
ddc723bb005fedc14687ee59879b2905b03271918361292aaf58f9a57a16d343
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 31886 bytes
vbaProject_00.bin
faf7108d1bdbb9d508495000f2fc270ae9bfefe3b4cd78e138317c5ecbaf5f59
vba-project OOXML VBA project: word/vbaProject.bin 34304 bytes
Detection
ClamAV: Xls.Dropper.Valyria-10012499-0
Obfuscation or payload: unlikely